| 岛礁吹填珊瑚砂力学行为与颗粒破碎特性试验研究 |
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| 引用本文： | 吴杨,崔杰,李能,王星,吴毅航,郭舒洋.岛礁吹填珊瑚砂力学行为与颗粒破碎特性试验研究[J].岩土力学,2020,41(10):3181-3191. |
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| 作者姓名： | 吴杨 崔杰 李能 王星 吴毅航 郭舒洋 |
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| 作者单位： | 1. 广州大学 土木工程学院，广东 广州 510006；2. 广州大学 广东省滨海软土地区地下结构安全防护工程技术研究中心，广东 广州 510006 |
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| 基金项目： | 国家重点研发计划项目（No. 2017YFC1500400）；中国工程院咨询研究项目（No.2019-XZ-18）；国家自然科学基金（No. 51908153，No.51778159）；广州市科技计划项目（No. 201904010278）。 |
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| 摘 要： | 珊瑚砂是岛礁陆域吹填唯一的材料，因其特殊的海洋生物成因和孔隙结构特征，珊瑚砂颗粒在常规工程应力水平下就会发生破碎。通过对取自南海某吹填岛礁的珊瑚砂开展室内三轴固结排水剪切试验，研究珊瑚砂强度、变形参数和颗粒破碎程度随相对密实度、围压的演变规律，并与其他研究成果中的南海珊瑚砂强度参数进行对比分析。研究结果表明：珊瑚砂应变软化及剪胀特征随有效围压的增大、密实度的减小而逐渐减弱；在常规应力范围内，得到珊瑚砂峰值摩擦角和临界状态摩擦角的取值范围分别为33o～58o和28o～47o，且均随有效围压的增大而减小；建立了珊瑚砂割线模量E50与相对密实度、有效围压间的关系式；珊瑚砂峰值摩擦角与修正相对破碎指数Br*间的关系可用指数为负数的幂函数关系式拟合，且当颗粒破碎程度较高时，峰值摩擦角随修正相对破碎指数的增大而减小的趋势变缓；珊瑚砂修正相对破碎指数随塑性功的增大近似以双曲线的形式增长，密实度对两者间的关系影响不大。该研究成果可为南海岛礁基础设施的安全设计提供参考。
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| 关 键 词： | 珊瑚砂 颗粒破碎 摩擦角 割线模量 围压 相对密实度 |
| 收稿时间： | 2020-05-13 |
| 修稿时间： | 2020-07-08 |
Experimental study on the mechanical behavior and particle breakage characteristics of hydraulic filled coral sand on a coral reef island in the
South China Sea |
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| WU Yang,CUI Jie,LI Neng,WANG Xing,WU Yi-hang,GUO Shu-yang.Experimental study on the mechanical behavior and particle breakage characteristics of hydraulic filled coral sand on a coral reef island in the
South China Sea[J].Rock and Soil Mechanics,2020,41(10):3181-3191. |
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| Authors: | WU Yang CUI Jie LI Neng WANG Xing WU Yi-hang GUO Shu-yang |
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| Institution: | 1. School of Civil Engineering, Guangzhou University, Guangzhou, Guangdong 510006, China; 2. Guangdong Provincial Engineering and Technology Research Center of Geo-Structure Safety and Protection, Guangzhou University, Guangzhou, Guangdong 510006, China |
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| Abstract: | Coral sand is the only material for island land reclamation. Due to its special marine biogenesis and porosity structure, coral sand particles are easily crushed at normal level of engineering stress. In this study, drained triaxial shear tests were carried out on coral sand retrieved from a reclamation reef in the South China Sea to study the evolution law of the strength, deformation and particle breakage properties of coral sand with different levels of density and confining pressure. The comparative analysis of shear strength index is made between current study and previous investigations. The results show that strain softening and dilatation tendency of coral sand gradually weaken with an increase in confining pressure and decrease in compactness. Within the normal confining pressure range, the values of the peak and critical state frictional angles of coral sand were 33o?58o and 28o?47o, respectively, both of which decreased with an increase in the confining pressure. The relationship among the secant modulus E50, relative density and effective confining pressure for coral sand was established. The relationship between the peak friction angle of coral sand and the modified relative breakage index (Br*) can be fitted by a power function equation with a negative index. When the extent of particle breakage is large, the decreasing trend of peak friction angle with an increase in the modified relative breakage index slows down. The correlation between the modified relative breakage index and plastic work for coral sand could be simulated using hyperbolic curve, and it is hardly affected by density. The research results can provide useful reference and technical support for island reclamation and infrastructure construction in the South China Sea. |
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| Keywords: | coral sand particle breakage frictional angle secant modulus confining pressure relative density |
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